This invention relates to a device for determining and/or checking the condition, state, and/or other parameters of a pressure fluid contained in a hydraulic system.
Such a device, e.g., is suitable for regular checking of the brake fluid's water content and thus of the brake fluid's effectiveness. As is known, the standard brake fluids are hygroscopic and will thus, amongst other things, permanently absorb moisture from the air via the brake piston seal. Thereby, within a relatively short time, its boiling point will drop from an initial value of 260.degree. to 290.degree. C. down to a value which, with a heavy usaage of the brake, may lead to the formation of vapor bubbles which may be compressed like normal air and will greatly impair the braking action. For the maintenance of a safe brake system it is thus necessary to regularly check the brake fluid. If no testing or measuring device is available this will require a relative frequent exchange of the fluid.
Until now, only relatively expensive and intricate devices are known which allow the brake fluid or samples taken from the brake system to be tested for their water content in the garage. As under favorable circumstances the fluid may age very fast or absorb an excessive amount of moisture, respectively, frequently the boiling point's dropping-down to dangerous values will be realized too late. On the other hand, an exchange of the fluid at very short intervals for the sake of ensuring the operational reliablilty of the brake system is likewise undesirable because of the costs incurred thereby.
It is thus an object of the this invention to provide a device which allows its installation in a hydraulic system and a regular checking of the pressure fluid's condition or state. In particular, the device shall be suitable for building-in into the brake system of automotive vehicles in order to check the boiling point of the brake fluid permanently or, as it were, continuously, e.g. daily, before starting a longer journey, or each time having travelled a predetermined route. A device which would be suitable for such applications would have to operate reliably. It would have to be up to the rough requirements in an automotive vehicle and, above all, it would have to permit its manufacture to be effected with a sufficiently small expenditure.